# File lib/facter/core/logging.rb, line 44
  def debug(msg)
    if self.debugging?
      if msg.nil? or msg.empty?
        invoker = caller[0].slice(/.*:\d+/)
        self.warn "#{self.class}#debug invoked with invalid message #{msg.inspect}:#{msg.class} at #{invoker}"
      elsif @@message_callback
        @@message_callback.call(:debug, msg)
      else
        puts GREEN + msg + RESET
      end
    end
  end